page_title: Macromolecular crowding
hierarchical_section_title: Macromolecular crowding
caption_attribution_description: English: Picture of cytosol, showing microtubules (light blue), actin filaments (dark blue), ribosomes (yellow and purple), soluble proteins (light blue), kinesin (red), small molecules (white) and RNA (pink).
context_page_description: The phenomenon of macromolecular crowding alters the properties of molecules in a solution when high concentrations of macromolecules such as proteins are present. Such conditions occur routinely in living cells; for instance, the cytosol of Escherichia coli contains about 300–400 mg/ml of macromolecules. Crowding occurs since these high concentrations of macromolecules reduce the volume of solvent available for other molecules in the solution, which has the result of increasing their effective concentrations. Crowding can promote formation of a biomolecular condensate by colloidal phase separation.
  This crowding effect can make molecules in cells behave in radically different ways than in test-tube assays. Consequently, measurements of the properties of enzymes or processes in metabolism that are made in the laboratory in dilute solutions may be different by many orders of magnitude from the true values seen in living cells. The study of biochemical processes under realistically crowded conditions is very important, since these conditions are a ubiquitous property of all cells and crowding may be essential for the efficient operation of metabolism.
context_section_description: The phenomenon of macromolecular crowding alters the properties of molecules in a solution when high concentrations of macromolecules such as proteins are present. Such conditions occur routinely in living cells; for instance, the cytosol of Escherichia coli contains about 300–400 mg/ml of macromolecules. Crowding occurs since these high concentrations of macromolecules reduce the volume of solvent available for other molecules in the solution, which has the result of increasing their effective concentrations.  Crowding can promote formation of a biomolecular condensate by colloidal phase separation.
  This crowding effect can make molecules in cells behave in radically different ways than in test-tube assays. Consequently, measurements of the properties of enzymes or processes in metabolism that are made in the laboratory (in vitro) in dilute solutions may be different by many orders of magnitude from the true values seen in living cells (in vivo). The study of biochemical processes under realistically crowded conditions is very important, since these conditions are a ubiquitous property of all cells and crowding may be essential for the efficient operation of metabolism. Indeed, in vitro studies showed that crowding greatly influences binding stability of proteins to DNA.
caption: Macromolecular crowding in the cytosol of cells alters the properties of macromolecules such as proteins and nucleic acids.[1]
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